Ofenpass Pine Stand (Winter): HET08_OPS_WIN
This page provides descriptions of the architectural, spectral and illumination related properties of a mountain pine (Pinus montana) stand located in the eastern Ofenpass valley of Switzerland. The forest stand features trees aged between 90 and 200 years and has been without management since 1914. The Ofenpass pine stand description provided below is based on inventory data gathered by the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), as well as, field and Lidar data acquired and processed by Felix Morsdorf, Ben Kötz and colleagues from the Remote Sensing Laboratories (RSL) of the University of Zurich, Switzerland. Potential RAMI participants are to treat the information presented on this page as actual 'inventory data', that is, they should identify/extract those parameters and characteristics that are required as input to their canopy reflectance models. In some cases this may mean that simplifications have to be made to the available information, or, that parts of the available information cannot be - or have to be modified before being - exploited with a given radiative transfer model. Whatever the case may be, all potential RAMI participants should mimic the standard practices that they use when matching actual field measurements to the required set(s) of input parameters for their model(s). If this means that you need more information than provided, please do not hesitate in contacting us. Last but not least, for those 3D models capable of maintaining architectural fidelity down to the individual shoot and branch level a series of ASCII (text) files containing the Cartesian coordinates of various geometric primitives (triangles, spheres and cylinders) and their transformations will be given.
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In order to facilitate the generation of the Ofenpass Mountain Pine stand (winter) the information on this page has been subdivided into four different categories. For each one of these categories the relevant descriptions will be contained within a uniquely coloured text frame and can be accessed by clicking on one of the four links below:
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In case of difficulties or missing data on this page please do not hesitate in contacting us so that the problems may be resolved as fast as possible.
Architectural information 
1) General canopy characteristicsThe Ofenpass Mountain Pine forest inventory was carried out over a large area from which a 100×100 m² subplot was selected for RAMI. The origin of the coordinate system was placed at the south-western end of this area. However, in order to include the tree crowns of those trees that were located within the 1 hectare area of the RAMI Mountain Pine Winter stand representation it was necessary to expand the scene area slightly beyond the one hectare. Maintaining the origin of the tree location coordinate system thus resulted in some negative x,y values in the table below. Overall architectural characteristics of the scene are thus as follows:
**The fractional cover is defined as 1 - direct transmission at zero solar zenith angle. 2) Foliage structureThe table below provides the architectural characteristics of the shoots of the trees used in the Ofenpass Pine stand representation. Individual shoots are generated by stacking four sub-shoots - with architectures based on the geometry proposed by Smolander et al., 2003 (RSE) - on top of each other. RT models capable of representing the architecture of individual foliage elements with a series of geometric primitives (triangle, sphere, cylinder) may want to use the information provided in the ASCII (text) files accessible from the last row in each table below.
3) Tree structureThe Ofenpass Mountain Pine forest is generated on the basis of 13 individual tree representations. Twelve of these pertain to live Mountain pine (Pinus Montana) trees and one refers to a dead Mountain pine tree representation. The latter is due to the fact that about 20% of the overall tree density is made up of dead (standing) trees. The table below provides an overview of some structural characteristics of these various tree representations. For those RT models capable of representing the 3D architecture of a given trees in a voxelised manner, or alternatively, through a series of geometric primitives the last four lines of this table contain links to data files with detailed specifications of the foliage and wood structural properties of the Ofenpass Mountain Pine forest (Winter) trees. TABLE 1:
TABLE 2:
4) Stand structureThe Ofenpass Mountain Pine forest is composed of 991 individual trees. The following table indicates how these trees are distributed among the above tree classes and specifies their respective x,y locations of the tree centers of each tree class in the forest stand. The last row of this table contains an ASCII file with tree rotation and translation information for those RT models capable of ingesting the detailed 3D architecture of the tree models specified in the previous section.
The Figure below shows the tree locations for the Ofenpass Mountain pine (Winter) stand. Crown of live trees are open circles. Red dots are trees belonging to the (randomly dispersed) understorey.
Black dots are (randomly dispersed) dead trees. The origin of the coordinate system is in the lower left hand side corner of the image.
![]() RAMI participants with 3D RT models capable of representing objects using geometric primitives can download a single compressed ZIP archive with all the tree architectural ASCII information that is listed in the above tables by clicking HERE. Note: The size of the compressed archive is about 1.8 megabytes. It contains 42 ASCII files and can be unzipped using 'WINZIP' on windows or 'unzip' on linux/unix operating systems. Beware that the inflated archive will take up 9.7 Megabytes of storage. |
spectral canopy characteristics 
Only the foliage and woody components in the Ofenpass pine stand (Winter) scene feature LAMBERTIAN scattering properties. The background properties on the other hand are NON-LAMBERTIAN. To capture the directional variability of the hemispherical directional reflectance factor (HDRF) of snow, the RPV model has been fitted to a series of actual goniometer observations. The tables below contains the magnitudes of the reflectance and transmission characteristics of the various canopy components for nineteen different spectral bands as well as the RPV parameters describing the anisotropy of the background HDRF. The experimental identifier for the Ofenpass Pine Stand (Winter) scene is given by HET08_OPS_WIN_B**_47 where B** relates to the spectral bands (B01, B02, …, B19). An ASCII (text) file that resumes all of this information can be found here.
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illumination characteristics 
The illumination conditions for the Ofenpass Mountain Pine forest stand feature both direct and isotropic diffuse components. Direct solar light is characterised by a solar zenith angle (SZA) of 47.0 degree and a solar azimuth angle equal to 151.3 degree. The table below indicates the ratio of isotropic diffuse to total incident radiation for the nineteen different spectral bands:
The figure below shows a perspective-free view of the Ofenpass Mountain pine stand with the Cartesian coordinate
system and the direction of the incident solar radiation (blue arrow) superimposed. Azimuth
angles are counted in an anti-clockwise direction from the positive X-axis towards the positive Y-axis
as indicated by the (dotted blue) arc around the origin. ![]() |
measurement characteristics 
Prior to the performing of any RT model simulations, please refer to the 'definitions' pages for detailed instructions regarding the angular sign conventions for BRF simulations, as well as other RT model technicalities. Also read the relevant file naming and formatting conventions that must be adhered to by all participants. In addition, RAMI-IV offers participants the possibility to test the compliance of their model-generated results files with these file-naming and formatting convention, prior to their submission via ftp: To do so follow the on-line format checker link that appears in the top navigation bar during the active submission period.